The outbreak started in Zambia and spread to South Africa.
Credit: Google Maps
BOSTON: Experts have identified a highly contagious and lethal new viral disease, which infected five people in Southern Africa. With some similarities to Ebola, the so-called Lujo virus may have passed to people from rodents.
According to a study in the journal PLoS Pathogens, Lujo causes 'hemorrhagic fever', which is a fever combined with heavy bleeding. It infected five people in Zambia and South Africa during September and October 2008, killing four of its victims.
"This mortality rate is extremely high," said Ian Lipkin, an epidemiologist at Colombia University in New York City, who co-authored the paper. His team are now trying to learn more about the virus, including how the first person became infected, its geographical distribution and possible treatments.
Rodent origin
The virus was characterised as an arenavirus, a family of viruses found in rodents. Other human viruses in the same family include the African Lassa virus and the South American Junin virus. It is the first new hemorrhagic fever-associated arenavirus to be discovered in three decades, the researchers reported.
The experts are unsure how the Lujo virus moved from rodents to humans, although Lipkin said such transfers are often aided by rodent excretion. Rodents are also eaten as bushmeat in some parts of Africa.
"Many viruses that persistently infect rodents are excreted in urine and faeces," said Lipkin. "Humans can be exposed by direct contact or aerosols."
The first case was in Zambia, and the affected individual was transferred to South Africa by plane. The paramedic who attended the patient during air transfer, the nurse who cared for the patient in the hospital, and the person who cleaned the room after the patient's death all succumbed to the virus.
Highly contagious
The fifth victim, a nurse who attended the paramedic, recovered after being given the drug ribavirin, which is used to treat the Lassa virus. However, it is unclear whether the medicine helped or whether she simply had a milder form of the disease.
The Lujo virus was named after the places of outbreak – Lusaka, Zambia and Johannesburg, South Africa. It was identified and characterised within 72 hours, the paper reports. A genetic sequencing technique called pyrosequencing was used to achieve this record-breaking speed of identification.
"These methods allow rapid identification and response to emerging infectious disease threats," Lipkin said. "Research that once took weeks can now be done in a few days."
To characterise the virus, researchers took genetic material from the victims' blood and livers. The pyrosequencing method allowed them to obtain detailed information about a sample's DNA without any advanced knowledge of it.
This method allowed researchers to analyze the new virus in "unprecedented" time scales, said Scott Layne, an epidemiologist with the University of California in Los Angeles. "It is extremely exciting and important work for emerging infectious diseases."
The next step, Lipkin said, is to use the genetic information to learn more about the Lujo virus. Researchers are trying to determine the geographic distribution, as well as find drugs that could be used as a treatment.
Right now, though, "we don't know how it causes disease or how to prevent or treat infection," he said.
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